Xcode 26.4 build issues

[ovyhlidal]

How frequently does the bug occur?

Always

Description

We are seeing a build break in Realm’s vendored s2geometry sources when building through realm-swift with Xcode 26.4.

Environment

• realm-swift: 10.54.6
• realm-core / RealmDatabase: 14.14.0
• Build system: xcodebuild
• Xcode: 26.4 (17E192)
• Compiler: Apple clang version 21.0.0 (clang-2100.0.123.102)
• SDK used during failing build: iphonesimulator26.4
• Target: iOS Simulator, arm64

Problem

The build fails in Realm’s vendored s2geometry C++ code because the current libc++ toolchain rejects specialization of std::is_pod.

This repeats for multiple types, including:

• S1Interval
• S2LatLng
• S2CellId
• S1Angle
• R1Interval

With Xcode 26.4, the build stops in Realm s2geometry with the std::is_pod specialization error.

With an older Xcode 26.3 toolchain, the same project gets past Realm compilation and fails later in unrelated app Swift code.

Stacktrace & log output

Can you reproduce the bug?

Always

Reproduction Steps

Just build version 10.54.6 with your swift project under Xcode 26.4 and it fails.

Version

10.54.6

What Atlas Services are you using?

Local Database only

Are you using encryption?

No

Platform OS and version(s)

ios 26.4

Build environment

Xcode version: 26.4
Dependency manager and version: SPM, Cococapods

[kpacholak]

isn't it the same issue? #8812